Evaluation of anticandidal potential of Quercus baloot Griff. using contact bioautography technique

The activities of fractions derived from hydroalcoholic extract of Quercus baloot leaves against a dimorphoic pathogenic yeast, Candida albicans (Cl. I. 4043) was evaluated. The hydroalcoholic extract was sequentially fractionated to give n-hexane, dichloromethane, ethylacetate, and n-butanol fractions, which were also subjected to qualitative phytochemical analyses. Preliminary anticandidal screening was carried out using disk diffusion assay with clotrimazole and chloroform serving as positive and negative controls, respectively. Using optimized solvent systems for each fraction, thin layer chromatography was done to separate the secondary metabolites that were evaluated for bioactivity using contact bioautography technique. Minimum inhibitory concentrations of the individual fractions were found using broth microdilution method. Preliminary screening showed all the fractions, apart from aqueous fraction, to have anticandidal potential (zone of inhibition ≥ 10 mm) against test yeast. However, contact bioautography revealed that only dichloromethane fraction was bioactive with inhibition zones at R f = 0.44 and 0.50, which showed location of inhibitory compound. The MIC of 125 µg/ml also support the presence of anticandidal moieties in this fraction. Phytochemical analyses indicated flavonoids, terpenoids, and steroids in the fractions.